Power steering pump



Oct. 1, 1968 H. M. CLARK ET AL 3,403,630

POWER STEERING PUMP 4 Sheets-Sheet l Filed Dec. 22, 1966 @3 @5 ATTORNEYS Oct. 1, 1968 H. M, CLARK ET AL POWER STEERING PUMP 4 Sheets-Sheet 2 Filed Dec. 22, 1966 NWN ct. 1, 1968 H M, CLARK ET AL. 3,403,630

POWER STEERING PUMP Filed Deo. 22, 1966 4 Sheets-Sheet 3 ay M, ,AZZ .a gg y v ATTORNEYS Oct 1, 1968 H. M. CLARK ET AL POWER STEERING PUMP 4 Sheets-Sheet 4 Filed DeC. 22, 1966 .imHilimllllllllull1 United States Patent O 3,403,630 POWER srEERiNG PUMP Hubert M. Clark and Gilbert H. Drutchas, Birmingham,

ABSTRACT OF THE DISCLOSURE This invention relates generally to pumps of the socalled slipper-type utilizing peripherally notched rotor carrying slippers which are free to move radially and rock angularly in following the cylinder wall of a pumping chamber and more specifically to a multiple pumping element pump wherein slipper engagement with the cylinder wall is provided by the slippers between the working chambers of the pump, thereby eliminating the necessity of a tangent seal between the rotor and the pump body. The pump -is further characterized by a pressure-loaded stackup of parts 'wherein the strain on the components of the stackup of parts is relieved by axially extending retainer bolts. The end cap of the stackup has a crossover passage affording a balanced pump arrangement.

Background of the invention (l) Field of the invention.-The invention pertains to improvements in positive displacement pumps having a variable chamber operating characteristic.

(2) Description of the prior drh-The prior art pertinent to the present invention is exemplified by the Clark and Drutchas Patent 3,200,752, issued Aug. 17, 1965, and also the Clark and Drutchas Patent 3,273,503, issued Sept. 20, 1966. The present invention distinguishes over such earlier developments through the provision of a slipper-type pump wherein the pressure seal between the pump inlet and outlet is accomplished by Slipper position atiorded through a multiple pumping element slipper arrangement. The slippers of the present invention are also of a simple symmetrical construction so they can be readily cut from a continuous extrusion. Strain on the components of the pressure-loaded stackup of parts is relieved by axially extending retainer bolts and the end cap of the stackup has a crossover passage affording a balanced pump arrangement.

S nmmary The pump of the present invention is particularly characterized by a stackup of parts arranged in an axial row relative to a housing ange having a iiat face and a plurality of axial bolts extend through the stackup of parts and are attached to the housing for absorbing hydraulic reaction of the pump. A large number of slippers of simple symmetrical construction are provided so that at least two slippers are in sealing engagement lwith the bore wall between the inlets and outlets of a double-lobed pump, thereby eliminating the necessity of a tangent seal between the rotor and the casing.

Brie]c description of the drawings FIGURE l is an end View of a pump provided in accordance with the principles of the present invention taken on the plane of line I-I of FIGURE 3;

FIGURE 2 is a cross-sectional view taken on line II-II of FIGURE l;

FIGURE 3 is a cross-sectional view taken generally on line III-III of FIGURE 1;

FIGURE 4 is a reduced cross-sectional view taken Igenerally on line IV-IV of FIGURE 3;

ICC

FIGURE 5 is a reduced cross-sectional view taken generally on line V--V of FIGURE 3;

FIGURE 6 is a reduced cross-sectional view taken generally on line VI-VI of FIGURE 3;

FIGURE 7 is a reduced cross-sectional view taken generally on line VII-VII of FIGURE 3.

Description of the preferred embodiment For the purpose of illustrating the principles of the present invention, a particularly useful application is made when the pump is incorporated in a hydraulic power assisting arrangement such as a power steering system of a dirigible vehicle. Thus, it is contemplated that a power steering pump shown generally at 10 is provided andthe pump has a can reservoir 11 formed with a iilling spout 12 closed by a cap 13, thereby permitting the can reservoir 11 to be filled with a requisite supply of fluid. The pump is further characterized by an oil return spout 14 which is adapted to return spent fluid from a point of utilization back, to the reservoir, and a pair of threaded bosses 15 for mounting the pump in a vehicle.

As will be noted upon referring to FIGURE 3, the pump of the present invention is particularly characterized by a stackup of parts including in a longitudinal row a pumping element cartridge 16, a pressure plate 17 and a cover plate 18. The pumping element cartridge 16 and the pressure plate 17 are held in axial alignment in a sandwiched arrangement between the cover plate 18 and a fiat face 19 of a housing tiange 20 by means of a bolted assembly which includes a stud bolt 21 extending through the stackup of parts and threadedly connected to the housing flange 20, as generally shown at 22. The other end of the stud 21 carries a nut 23 and a lock Washer 24 which snugly t against the cover plate 18 for maintaining the sandwiched arrangement at the stackup of parts. One of the studs 21 has a portion 21a extending through the can reservoir 11 and carrying a nut 23a for maintaining the position of the can reservoir 11 relative to the stackup of parts. A boss 18a is provided on the cover plate 18 and a gasket 23b is shown between the boss 18a and the can 11 as well as under the nut 23a.

The cover plate 18 and the pressure plate 17 are separated by a thin gasket member 25 which may consist of any suitable gasketing material with the requisite elasticity and physical properties contemplated by the present invention. A thin, ilexible shell member 26 surrounds the peripheries of the pumping element cartridge 16 and the pressure plate 17 and has one of its ends sealingly abutting the gasket member 25 as generally shown at 27, and has its other end 2S formed as a radially outwardly turned portion engaging a sealing member 29 which eiects a pressure seal between the housing flange 20 and the'shell member 26. The primary function of the stud bolt arrangement is to absorb any hydraulic reaction of the pump. The bolt torque tension in sandwiching the pumping element cartridge 16 and the pressurel plate 17 between the cover plate 18 and the ilat surface 19 of the housing flange 20 need be only such as to prevent bolt loosening. The use of the bolts eliminates the necessity of using a strong thick casing since the bolts 21 take thel sumes the general cross sectional configuration of an oval and, in cooperation with a circular rotor 32 disposed therein, prescribes pumping chambers at the respective oblong ends as shown generally at 33.

The rotor 32 is generally cylindrically shaped and has a plurality of peripheral notches shown generally at 35. Each specific notch includes a bottom wall 36 and substantially parallel side walls each indicated at 37. The bottom wall 36 has a recess 3S in which is bottomed a coil spring 39 adapted to continuously bias Ia slipper element shown generally at 40 radially outwardly to a sealing engagement with the adjoining cylinder wall 31.

In accordance with the principles of the present invention, the slippers 40 are of a specific structural shape in that each slipper member is an elongated extrusion which in cross section is somewhat rectangular and having a pair of curved walls shown at 41 which are oppositely disposed and an arcuate inner wall 42 for bottoming one end of the bias spring 39, and permitting the spring to move freely and an arcuate outer wall 43. Thus the inner side walls 41 and the outer wall 43 of each respective slipper meet at points indicated at 44 and 45. Referring now to the inner walls 41, it will be noted that the diameter of curvature is substantially equal to the width of a corresponding notch 35. The size of the slipper is controlled so that each slipper 40 is free to move radially and rock angularly with respect to the notch and the rotor 32 in following the contour of the cylinder wall 31.

Each arcuate surface 43 extending between the points 44 and 45 is of a curvature substantially Vthe same as the curvature of the cylinder wall 31. However, the curvature of the arcuate surface 43 is just slightly less than the curvature of the joining cylinder wall 31 in order to attain the classic Kingsbury effect, namely, a film of oil is introduced under the leading edge of the slipper, thereby permitting the arcuate surface to ride on a film of oil. The cross section of the slipper is further characterized Ias being entirely symmetrical from top to bottom, and may be formed by merely cutting an extrusion to the proper selected length.

A-s contemplated by the present invention, ya multiple pulse arrangement is achieved since there is alway a slipper 40 in sealing engagement with the cylinder wall 31 exposed in the pumping chamber 33 at any rotatable position of the rotor 32 between the inlet and the outlet. This provides a good seal and eliminates the necessity of providing tangential seals between the rotor and the adjoining pumping chamber wall, thereby allowing greater tolerances between the rotor 32 and the cylinder wall 31.

It will be noted that the ring member 30 has peripheral recesses shown generally at 46 for receiving the studs 21 and is further provided with openings for receiving dowel pins shown generally at 47.

The outer peripheral surface of the ring 30 also has a portion 48 which projects radially outwardly at one side and in which are formed the discharge passages and flow control valve cavity in accordance with the principles of the present invention. Peripheral portions of the ring member 30 are surrounded by the shell member 26, thereby forming a pump inlet zone I which is filled with pumping media.

Referring to FIGURES 2, 3, 4 and 6, the peripheral extent of the pressure plate 17 is such that the inlet zone I surrounds portions thereof. The pressure pla-te 17 is provided with a pair of radially inwardly projecting openings 49 to provide side inlets to the notches 35 at a point `radially inwardly of the slippers 40. A plurality of peripheral recesses 51 accommodate the stud bolts 21 and a pair of openings 52 receive corresponding dowel pins. The dowel pins extend substantially throughout the stack of parts and Aanchor in the liange member 20 thereby providing means for maintaining axial alignment of the stackup of parts.

The -pressure plate 17 also has a major and minor pumping chamber outlet design-atedat 53 and 54, respectively, and which communicate with the pumping chamtal 'ber 33 and the notches 35, respectively. One of the major ports 53 is formed with a radially outward extension shown generally at 55.

Referring to FIGURE 7 the cover plate 18 is of substantially circular construction having sufcient diameter to protrude radially outwardly beyond the end of the llexible shell member 26 as best seen in FIGURE 6, thereby providing an end wall for the inlet zone I. Circumlferentially spaced openings 56 are provided through which pass the axial stud bolts 21. The cover plate 18 is provided with a recess or crossover passage 57 which in cooperation with the underlying pressure plate 17 prescribes a discharge zone D and interconnects the diametrically opposed outlets 53 and 54. The discharge zone D is of suflicient extent whereby the pressure acting upon the exposed portion of the pressure plate 17 will pressure load the stackup of parts into a nonleaking assembly.

Referring to FIGURE 4, it will be `seen that the pressure zone D in the recess 57 formed in the cover plate 18 is in fluid communication with an outlet zone designated at O which is formed by the passage in the pressure plate 17. The outlet zone O has an orifice outlet formed in an orifice plate member 60 which is press fit in a recess formed in the pressure plate 17 as shown generally at 61. The outlet orifice 59 opens to a discharge passage opening in the cover plate 18 as a passage 58. An opening 63 formed in the ring member 30 is in alignment with the opening 62. The discharge passage is further defined by a recess 64 formed in the housing flange 20 which is intersected by an angled passage 65 counter- `bored at 66 to receive a fitting 67 and partially threaded as at 68 so that a conduit may be connected thereto for carrying pump generated pressure to `a point of utilization.

The ring member 30 has formed therein a notch 69 which intersects with a separate series of passages formed in the stackup of parts and provided for housing a control valve assembly. In this regard it will be noted that the flange 2G has formed therein a recess 70 having a flat bottom 71 for bottoming one end of a coil spring 72. The other end of the coil spring 72 overlaps a shoulder 73 of a valve member 74 which is slidably guided in an laxial opening 75 formed in the ring member 30. It will be noted that a valve stop is provided by the abutting surface of the pressure plate 17 which forms a shoulder relative to the opening 75, as shown at 76, A valve shoulder 77 is for-med in the recess 70 on the other side of the valve member 74.

The valve member 74 has formed therein a flat surface as shown at 78 from which projects a valve stem 79 which extends through the outlet orifice 59. The slotted passage 69 communicates discharge pressure to the chamber defined by recess and to a side 80 of the valve member 74.

Pump generated pressure in discharge zone D is communicated to the outlet zone O which acts upon surface 78 of the valve member 74. Thus, it will be appreciated that the pressure upstream of the outlet orifice is in communication with surface 78 of the valve member 74 while the downstream pressure is in pressure communication with the other side of the valve member 74.

The valve member 74 has formed therein a recess 81 having a flat bottom 82 for bottoming one end of a coil spring 83. The other end of the coil spring 83 engages a ball valve 84 which normally engages a plug adjustably press fit in the valve member 74 to form a valve seat 85 thereby to regulate llow of fluid through a passage 86.

The valve member 74 is peripherally recessed to form an annulus at 87 to provide a control land for regulating the intercommunication of the outlet zone O with a pair of outwardly extending openings designated at 88. As best seen in FIGURE 5 the openings 88' discharge into inlet zone I.

In this regard the ring member is provided with a pair of angularly disposed aspirating passages 89, each of which intersects a corresponding passage 8S, and angles downwardly into a convergent disposition so that the opposite ends of the aspirating passages 89 lie in register with an opening 90 formed in the shell member 21. The aspirating flow which results assists in keeping the inlet zone I filled with fluid to be acted upon by the pumping unit.

As shown in FIGURE 3, the housing flange 20 is recessed at 91 to receive and seat a sealing gasket 92 which engages and seals against the reservoir can 11 and against the flange 20. Thus, a reservoir R surrounds the stackup of parts. Itwill be understood that a spout 14 (FIGURE 1) can be provided for connection to a return line so that spent fluid may be returned to the reservoir from the point of utilization.

Referring specifically to FIGURE 3, the housing flange is seen to have a boss means 93 which along with a main body portion has formed therein an opening 94 for carrying a shaft bushing shown generally at 95 and characterized by a sleeve-like shell having a bearing liner 96. The shaft 94 has a splined portion shown generally at 97 connected to the rotor 32 at 98 and has an extension 99 which has a flat radial surface 100. The flat surface 100 engages one radial Wall of the pressure plate 17 thereby permitting the pressure plate 17 to absorb thrust loads. The shaft 94 is retained in assembly with the rotor 32 of the pumping element cartridge by means of a snap ring 101.

A shaft seal is shown generally at 102 and is contained in the end of the boss 93. The outer end of the shaft 94 may be connected to a driving source for example a pulley having a drive connection to the V-belt drive of an automotive engine.

In operation, the outlet flow from the pumping charnbers 33, passes through the pressure -plate outlets 53 and -54 'which lie in register with the cover plate recess 57 prescribing the discharge zone D. The flow from one of the diametrically opposed pairs of outlets comprising openings 53 and 54 crosses over through the passage formed by the recess 57 to the other outlets where the flow commingles and passes to the outlet zone O which is formed by the radially outwardly extending portion 55 of the outlet 54.

From the outlet zone O where the fluid is in pressure communication with one side 78 of the valve member 74, the fluid passes through the outlet orifice 59 into the discharge passage formed by openings 58, 62, 63, 64, 65 and hence to the discharge opening 68. Fluid under pressure downstream from the outlet orifice is communicated to the other side 80 of the valve member 74 through the notched opening 69.

Thus, it will be understood that upstream and downstream pressures referred to the outlet orifices 59 are communicated to opposite sides of the valve member 74. The movement of the valve member 74 in response to the differential pressure opens or closes the bypass passage 88. Since the differential pressure is a function of flow through the orifice 59, the valve response thereto provides an effective means for regulating the flow through the orifice outlet 59 and hence to the point of utilization as, for example, a power steering unit.

Excess flow causes a pressure buildup on the fiat side 78 of the valve member 74 forcing the valve member 74 against the bias spring 72 until the bypass passages 88, 88 are cleared causing the excess flow to dump into the bypass passages 88, 88 and to the return inlet zone I.

The bypass passages 88, 88 are intersected by aspirating passages 89, '89 which are in register with makeup passages 90, 90. There is thus produced an aspirator eflect which insures filling from the inlet areas of the inlet zone I with sufficient supply of fluid. The combined makeup oil and bypass flow discharges into the inlet zone I which floods the radial inlets 34, 34 and the side inlets 49, 49.

Fluid at pump generated pressure in the discharge zone acts on the exposed pressure plate 17 which forms the bottom of the pressure zone D thereby assisting in holding the stackup of parts together and eliminates the necessity for additional sealing means since the parts can be retained in face to face sealing engagement with one another. In other words, as soon as the pump begins to operate and pump generated discharge pressure is communicated to the pressure zone D, it -will be evident that sealing, accomplished by surface-to-surface face seals, is actuated by the pressure in the pressure zone D squeezing the parts of the cartridge assembly together thereby minimizing the need for elastic sealing members to prevent leakage and bolts or other fasteners to hold the stackup assembly together.

A relief valve function is developed by the valve construction as shown specifically in FIGURE 4. Thus, the pressure in the recess 70 acts through the passage 86 and the valve seat on the ball 84 against the spring 83 when the spring force, suitably adjusted by press fitting the plug 8S, is overcome, pumping fluid flows through the passage 86 around the ball 84 and into the annulus 87. From thence the fluid passes through the bypass passages 88, 88 and zone I. Since all of the passages are greater in area than the notch or slotted passage 69 which feeds the recess 70, the pressure will drop in recess 70 below that of the zone O. Thus, the valve member 74 will move against its loading spring 72 and will open the zone O to the zone I through the bypass passages 88, 88, thereby bypassing excess oil.

Although various minor modifications might be suggested by those versed in the art, it should be understood that we Wish to embody Within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.

We claim as our invention:

1. In a pump,

a stackup of parts including:

a housing flange having a flat face,

a ring part having one side axially abutting said housing flange and having a contoured bore `wall forming a pump chamber,

said ring part having inlet areas to said pump chamber,

a pressure plate on the other side of said ring part having -formed therein outlet areas,

a ycover plate abutting the other side of said pressure plate and having recesses in register with said outlet areas for directing fluid from said outlet areas to a discharge passage,

a thin sheet form member shaped to form a shell surrounding the said ring part and the said pressure plate and cooperatively arranged with the said ring part and said pressure plate to form an inlet Zone,

and having its respective ends in abutment with the said flat face and the said cover plate,

a notched rotor in said ring part having a slipper means in the notched portion free to move radially and rock angularly in following the bore contour to move fluid from the said inlet areas to the said outlet areas,

means to rotate said rotor comprising a rotatable shaft connected to said rotor,

and support means for journalling said rotor.

2. In a pump as defined in claim 1,

said pressure plate having radially inwardly extending passages for directing fluid from the said inlet zone to the said pumping chamber at a point radially inwardly of the said slipper means,

the said ring member having radial inlet passages for directing fluid from the said inlet Zone to said inlet area o-f the said pumping chamber.

3. In a pump as defined in claim .1,

said pressure plate having pairs of outlets extending axially therethrough,

one of said outlets disposed to receive pump generated fluid from the periphery of the said rotor,

smarts@ 1 the other of the said outlets disposed to receive pum generated fluid from 4the said notches. 1 4. In a pump as dened in claim 1, said ring parts having a portion radially outwardly o ."the 'downstream side `ofvsaid oricebeing in communicationwith one side of said valve thereby to control the operation of the valve as function of fiow.

said bore wall formed with an axial opening, and 8. A pump comprising: f a flow regulator valve in said axial opening. a ring' member and a pressure plate sandwiched be- 5. In a pump as `delined by claim 1, v tween a housing flange and a,-cover-cap member, all said pressure plate being piloted on the end of said disposed in an axial row,

shaft and abutting the end of said shaft to absorb l a shaft journalled in said housing ange and having a shaft thrust loads, 10' t 'peripherally-notched rotor in said ring member, and a plurality of axial bolts extending through the said rotor carrying slipper means in the periphersaid stackup of parts and attached to the said housally notched portion free to move radially and ing ange for absorbing hydraulic reaction of the iv` rock angularly in` Ifollowing the cylinder Wall pump. of the ring member, i

6. A pump comprising: a thin shell member surrounding the said ring mema ring member -formed with a cylinder wall prescribing ber and said pressure plate and having its respeca pumping chamber, tive ends abutting the said housing flange and sai said ring member having radial inlets in comcover cap member,

munication |with said pumping chamber,I the interior of said shell member prescribing an a rotor in said pumping chamber having peripheral inlet zone surrounding said plate members,

notches formed therein, said cover cap member having recesses therein preslipper means in said peripheral notches free to move scribing a high presure discharge zone adjacent -radially and rock angularly in following the cylinder said pressure plate, l wall upon rotation of the rotor, t i said pressure plate having an outlet port extenda housing member providing a hat radial wall abutting ing in an axial direction communicating said one side of said ring member, pump chamber with said discharge zone to disa pressure plate having one side abutting the other charge pump generated pressure into said disside of said ring member and having axial outlet charge zone, ports formed therein, said plate members and said housing flange havsaid outlet ports in register with said pumping ing an axially extending discharge passage chamber, formed therein for conducting uid from said a cover plate having a radial wall abutting the other discharge zone to a point of utilization,

side of the said pressure plate, aflow control valve extending axially through said said cover plate having recesses formed therein plate members and having one end thereof subject in register with said outlet and cooperably arto said `discharge pressure zone and having the opranged with said pressure plate to form a pressure zone adjacent the said pressure plate, a thin shell member surrounding the peripheries of posite end4 thereof communicating with the pressure l in said discharge lpassage,

said discharge passage having a ow orilice therein,

the said ring member and the said pressure plate and whereby said ilow control valve regulates the flow of uid having its respective ends abutting the said housing 40 from said discharge zone to said inlet zone as a funcmember and the said cover plate, tion of ow through the discharge passage,

said shell member spaced radially Outwardly 0f and means for maintaining axial alignment of the said portions of said ring member and Said pressure plate members with respect to the said housing ange plate wherein the space prescribed by the inand the Said cover cap member. terior of said shell `member and the peripheries 9, A pump as defined in claim 6, of said ring member and said pressure plate said shell member having a .makeup opening formed constitutes an inlet zone, therein, a shaft journalled in said housing and corotatably one of Said plate members having bypass passages connected to said rotor for rotatably driving Said formed therein controlled by said flow control valve rotor to move fluid from said inlets in said ring and .further including aspirating passages formed member to said outlet ports, therein intersecting said bypass passages and open- Sld ring member and Said PfeSSllfe Plaie having ing adjacent said makeup passage to induce an aspiarl aXially eXieIifiiIlg diSCliaTge Passage formed rating ow through said makeup passage into said therein, inlet zone, and Seid hOUSiDg haViUg a radially directed Outlet Pori 5'5 means forming a reservoir surrounding said plate memfOrmed therein Ol` Connection t0 e Point 0f bers and said cover cap member and ilooding said utilization, makeup opening with tluid. means forming a reservoir around said ring member, 10 In a pump as defined in claim 1,

Stilid Pressure Plaie and Said Cover Plaie, n said rotor having suticient number of slippers and dis- Said Shell member having makeup Openings 1li com' 60 posed to provide at least two slippers in sealing en- Hllllieeiion With Seid inlet Zone t0 Supply Pump' gagement upon the .said bore wall between the said ing lluid thereto 4inlets and the said outlets at any rotatable position and means for maintaining axial alignment of the said of the rotor relative to the said bore .Wan

housing member, said ring member and said pressure 1L In a pump as defined in claim 1,

plate and said cover Plate said slippers'formed in the configuration of elongated .7' pump as dend in Claim 6" extrusions having a symmetrical cross section and said ring member having bypass passages formed therehaving an arcuate face disposed to follow the com tour of the said bore wall.

said pressure plate and said ring member having a Y I t valve bore extending axially therethrough, 12311113 Pump stackul? of Parts compilsilng m an axial row: p

a housing plate, l

a pumping element cartridge,

a pressure plate, 4. a cover plate having recesses formed therein and cosaid valve bore having a valve axially movable therein to control the discharge of overow excess from said `discharge zone into said bypass passages and said discharge passage having a tlow `restricting orilice contained therein,

operatively arranged with the said pressure plate to form a high pressure zone,

means for ymaintaining axial alignment ofthe said stackup of parts,

a thin sheet form member surrounding the said pumping element cartridge and said pressure plate and forming in cooperation with the peripheries of said pumping element cartridge in said pressure plate a low pressure inlet zone,

said stackup of parts being maintained in axial position by means of a bolted assembly arrangement including:

a plurality of studs extending axially through the said stackup of parts and each respective stud having one end ixedly attached to said houslng,

a nut adjustably carried by the other end of eac-h of the said studs,

and wherein the alignment of parts of the said stackup of parts is maintained by doWel pins extending axially through the said stackup of parts, whereby pressure in the lhigh pressure zone squeezes the parts comprising the stackup of parts into an operative assembly without the need of additional fasteners.

References Cited UNITED STATES PATENTS 3,125,028 3/1964 Rohde 103-42 3,175,506 3/1965 Erdmann 10B-136 3,184,156 5/1965 Welch et al. 1013-136 X 3,273,503 9/1966 Clark et al 10B-42 FRED C. MATTERN, JR., Primary Examiner. W. J. KRAUSS, Assistant Examiner. 

